Japanese Patent Laid-Open No. 2003-261808 discloses an oil-based inkjet ink improved in storage stability, which comprises a solvent 60% by weight or more of which is constituted by a polar organic solvent, in which 10% by weight or more of the polar organic solvent is constituted by an ester solvent.
However, when printed matters such as pamphlets are prepared by laying a print printed by the above inkjet ink on a print printed by a plane paper copier or a laser printer with the printed surfaces of the prints facing each other, there has been a problem that the printed surfaces are stuck to each other.